Field of the Invention
The present invention relates to an organic light emitting display device, and more particularly, to an organic light emitting display device that may improve outdoor visibility of a display panel.
Discussion of the Related Art
Recently, with the advancement of the information age, importance of a flat panel display (FPD) device having excellent characteristics such as a thin profile, light weight and low power consumption has been increased. Examples of the flat panel display device include a liquid crystal display (LCD) device, a plasma display panel (PDP) device, and an organic light emitting display (OLED) device. Recently, an electrophoretic display device (EPD) has been widely used as the flat panel display device.
Among the devices, the liquid crystal display device and the organic light emitting display device, each of which includes a thin film transistor, have been commercially used as display devices of television, notebook computer, tablet computer, or desk top computer owing to their excellent properties in resolution, color display and picture quality. Particularly, the organic light emitting display device is a self light emitting display device, and has received attention as a next generation flat panel display device owning to low power consumption, a fast response speed, high light emission efficiency, high luminance and a broad viewing angle.
The organic light emitting display (OLED) device may be categorized into a top emission type and a bottom emission type depending on a direction to which light emitted through an organic light emitting diode is transmitted.
The bottom emission type organic light emitting display device of the related art includes a base substrate, a thin film transistor (TFT), an organic light emitting diode (OLED), and an encapsulation layer. The gate and data lines are provided on the base substrate so as to cross each other to define a pixel, and the thin film transistor is provided in each pixel. The thin film transistor includes an active layer, a gate insulating film, a gate electrode, an interlayer dielectric, a source electrode and a drain electrode, which are sequentially deposited. The organic light emitting diode (OLED) is provided on the thin film transistor, and is electrically connected to the drain electrode of the thin film transistor. The organic light emitting diode includes an anode electrode, an organic light emitting layer, and a cathode electrode. The encapsulation layer protects the thin film transistor and the organic light emitting diode from external impact.
In the aforementioned bottom emission type organic light emitting display device of the related art, external light entering a display panel is reflected toward the outside of the display panel by electrodes provided inside the display panel. For this reason, outdoor visibility of the display panel may be deteriorated. To improve outdoor visibility, in the bottom emission structure, a polarizer should be arranged on a lower surface of the base substrate, to which light is emitted. However, there is a problem that the luminance of the display panel decreases due to the polarizer.